1. Field of the Invention
The present invention relates to a cooling system for an electric vehicle, and more particularly relates to a cooling system for an electric vehicle with improved cooling performance for an air-cooled electrical component mounted on the electric vehicle and a cooling method for the electrical component.
2. Description of Related Art
An electrical component such as a high-voltage battery, a charger, and a DC/DC converter is mounted on an electric vehicle such as a hybrid vehicle and a plug-in hybrid vehicle. These electrical components generate heat during operation and hence need to be cooled by a cooling system.
A conventional cooling system for an electric vehicle cools an electrical component in such a manner that the electrical component having a heat dissipating fin is disposed inside a box having an air inlet and an air outlet located in substantially the same position; a cooling duct covering the heat dissipating fin of the electrical component is attached thereto to form a substantially U-shaped air passage; and air is circulated through the air passage by an air blowing fan connected to the air inlet (see JP 2000-40535 A).
As disclosed in JP 2000-40535 A, the cooling system for an electric vehicle forcibly circulates air through and over the heat dissipating fins contacting a heat generating portion of the electrical component by the fan for cooling.
The cooling system for electrical components can cool the portions subjected to high temperature simply by circulating air through the heat dissipating fins. However, in a case in which the electrical component is disposed inside the box, the air inside the box is heated to high temperature by heat dissipation from a portion other than the heat dissipating fins of the electrical component. Then, when the electrical component is exposed to high temperature air, the thermal burden imposed on the electrical component increases.
In order to prevent a rise in air temperature around the electrical component, it can be considered to add not only a fan for cooling the electrical component but also a ventilation fan to ventilate the inside of the box. Unfortunately, addition of another ventilation fan is disadvantageous in that the mounting space and costs are increased.